Long chain diacids (“LCDAs”; also referred to as long chain dicarboxylic acids and long chain dioic acids) include diacids with the formula HOOC(CH2)nCOOH in which n≦7. LCDAs are used in the manufacture of a number of products and intermediate products, including polyamides, also known as nylons, used in making electric cable sheathes, tooth brush fibers; adhesive and performance coatings such as those used in co-polyamide adhesives, polyester adhesives, and paints; as GMA powder coat crosslinkers for automobile wheels; as anti-corrosion materials such as metal working fluids and those used in industrial cooling systems; synthetic lubricants, such as automobile lubricants; and in various personal care and household products, such as fragrances and household cleaners.
Chemical synthesis methods for long-chain alpha, omega dicarboxylic acids are available, but the methods are not easy and most of them result in mixtures containing acids having shorter chain lengths. Thus, extensive purification steps are necessary when producing LCDAs using these methods. Several strains of yeast are known to produce LCDAs when cultured on alkanes or fatty acids as the carbon source. There are three biochemical processes by which yeasts metabolize alkanes and fatty acids: α-oxidation of alkanes to alcohols, omega-oxidation of fatty acids to alpha, omega-dicarboxylic acids, and the degradative β-oxidation of fatty acids to CO2 and water. Biological conversion processes for the production of diacids have a number of potential advantages over non-biological conversion processes. Primary among these is the option to use renewable feedstocks as starting materials and the ability to produce the diacid without the generation of hazardous chemical byproducts which necessitate costly waste disposal processes. Another important advantage achieved by using a biological process is that such a process can easily be adapted to produce a wide variety of diacids using the same biocatalyst and the same equipment. Because current organic chemical syntheses are suited to the production of only a single diacid, the synthesis of several different diacids would require the development of a new synthetic scheme for each diacid. On the other hand, a yeast biocatalyst can be used to produce diacids of varying lengths using the same equipment, media and protocols merely by providing a different substrate to the yeast.
Despite advances in increasing the yield of dicarboxylic acids obtainable by culturing yeasts such as Candida tropicalis strains, there remains a need to provide higher-yielding strains of Candida for the production of long chain dicarboxylic acids, including undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, and octadecanedioic acid. It is accordingly an object of the invention to provide new strains and methods of using those strains to produce one or more long chain dicarboxylic acids. Using higher yielding strains of Candida to produce long chain dicarboxylic acids allows the ordinary artisan to replace the multi-step synthesis used in chemical methods with a higher yielding approach that nevertheless is achieved with low energy consumption and does not require a petrochemical starting material, although such materials may be used in the methods of the invention.